a. Field of the Invention
This invention relates to shaped articles exhibiting high surface hardness, having a dyeable surface, and additionally having antistatic, antifogging and/or antireflection properties, as well as a method of making such shaped articles. The shaped articles of this invention can be used in various industrial fields including, for example, architectural interior finishing and electronic fields.
b. Description of the Prior Art
Generally, organic polymeric materials have many advantages such as light weight, high impact resistance and good processability, and are hence being used in wide applications.
However, ordinary organic polymeric materials are softer than inorganic materials such as metals and glass. Thus, they have the disadvantage that their surface is subject to damage.
Accordingly, it has heretofore been proposed to provide the surfaces of shaped articles of organic polymeric material with a cured coating of a multifunctional monomer.
Such a cured coating of a multifunctional monomer exhibits high surface hardness, but has several disadvantages. Specifically, (1) it is very difficult to dye the coating. (2) The coating tends to build up electrostatic charges and, therefore, the surface of the shaped article tends to attract dust and dirt. This poses problems when the shaped article is used as a windowpane of a clean room or as an antireflection material for use in front of CRTs and LCDs. Moreover, (3) The coating tends to become foggy when the surface temperature of the shaped article is lower than the dew point of the environment. The problem of poor dyeability is due to the fact that the dense network structure of the cured coating prevents the penetration of dye molecules, and the problem of fogging is due to the fact that the surface of the cured coating lacks hydrophilic groups such as acidic groups. Meanwhile, a number of methods for introducing acidic groups into linear high polymers are known in the prior art. They include, for example, chromic acid treatment of polyethylene Souhenug Wu: "Polymer Interface and Adhesion" (1982)!, oxygen plasma treatment of polyethylene Nuzzo: Macromolecules, 17, 1013 (1984)!, grafting of acrylic acid onto polyethylene terephthalate by means of a low-temperature plasma Bradley: Vacuum Technology, March, 53 (1981)!, photo-induced graft polymerization of (meth)acrylic acid onto a polyolefin compound coated with a sensitizer Hagiwara: J. Plym. Sci. Poly. Lett. Fd., 19, 475 (1981)!, irradiating a polymer having sulfonyl groups with ultraviolet light (Japanese Patent Publication No. 1601/1987), and alkali hydrolysis treatment of polyacrylonitrile type high polymers Japanese Patent Publication Nos. 17151/'76 and 42916/'77!. In adition, the surface modification of polyethylene terephthalate by utilization of depolymerization with short-wave ultraviolet light S. Lazare: J. Am. Chem. Soc., 106, No. 15, 4288 (1984)! is also known.
However, these treating methods have various disadvantages. Specifically, chromic acid treatment is effective only for polyethylene and the like. Plasma treatment generally requires expensive equipment and must be performed under reduced pressure. Photo-induced graft polymerization have many restriction on operating conditions, such as the necessity of effecting the reaction in a monomer or in a high concentration of monomer. Alkali hydrolysis treatment is effective only for readily alkali-hydrolyzable polymers.
Moreover, where acidic groups are introduced into linear high polymers according to the above-described methods, it is impossible to achieve a sufficient level of hardness.